drivers/power/bq27x00_battery.c - kernel/msm-4.9 - Gitiles

 /*
  * BQ27x00 battery driver
  *
  * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
  * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
  *
  * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
  *
  * This package is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
  */
 #include <linux/module.h>
 #include <linux/param.h>
 #include <linux/jiffies.h>
 #include <linux/workqueue.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/idr.h>
 #include <linux/i2c.h>
 #include <asm/unaligned.h>

 #define DRIVER_VERSION			"1.1.0"

 #define BQ27x00_REG_TEMP		0x06
 #define BQ27x00_REG_VOLT		0x08
 #define BQ27x00_REG_AI			0x14
 #define BQ27x00_REG_FLAGS		0x0A
 #define BQ27x00_REG_TTE			0x16
 #define BQ27x00_REG_TTF			0x18
 #define BQ27x00_REG_TTECP		0x26

 #define BQ27000_REG_RSOC		0x0B /* Relative State-of-Charge */
 #define BQ27000_FLAG_CHGS		BIT(7)

 #define BQ27500_REG_SOC			0x2c
 #define BQ27500_FLAG_DSC		BIT(0)
 #define BQ27500_FLAG_FC			BIT(9)

 /* If the system has several batteries we need a different name for each
  * of them...
  */
 static DEFINE_IDR(battery_id);
 static DEFINE_MUTEX(battery_mutex);

 struct bq27x00_device_info;
 struct bq27x00_access_methods {
 	int (*read)(u8 reg, int *rt_value, int b_single,
 		struct bq27x00_device_info *di);
 };

 enum bq27x00_chip { BQ27000, BQ27500 };

 struct bq27x00_device_info {
 	struct device 		*dev;
 	int			id;
 	struct bq27x00_access_methods	*bus;
 	struct power_supply	bat;
 	enum bq27x00_chip	chip;

 	struct i2c_client	*client;
 };

 static enum power_supply_property bq27x00_battery_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 	POWER_SUPPLY_PROP_CAPACITY,
 	POWER_SUPPLY_PROP_TEMP,
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
 };

 /*
  * Common code for BQ27x00 devices
  */

 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
 			struct bq27x00_device_info *di)
 {
 	return di->bus->read(reg, rt_value, b_single, di);
 }

 /*
  * Return the battery temperature in tenths of degree Celsius
  * Or < 0 if something fails.
  */
 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
 {
 	int ret;
 	int temp = 0;

 	ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
 	if (ret) {
 		dev_err(di->dev, "error reading temperature\n");
 		return ret;
 	}

 	if (di->chip == BQ27500)
 		return temp - 2731;
 	else
 		return ((temp >> 2) - 273) * 10;
 }

 /*
  * Return the battery Voltage in milivolts
  * Or < 0 if something fails.
  */
 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
 {
 	int ret;
 	int volt = 0;

 	ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
 	if (ret) {
 		dev_err(di->dev, "error reading voltage\n");
 		return ret;
 	}

 	return volt * 1000;
 }

 /*
  * Return the battery average current
  * Note that current can be negative signed as well
  * Or 0 if something fails.
  */
 static int bq27x00_battery_current(struct bq27x00_device_info *di)
 {
 	int ret;
 	int curr = 0;
 	int flags = 0;

 	ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
 	if (ret) {
 		dev_err(di->dev, "error reading current\n");
 		return 0;
 	}

 	if (di->chip == BQ27500) {
 		/* bq27500 returns signed value */
 		curr = (int)(s16)curr;
 	} else {
 		ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 		if (ret < 0) {
 			dev_err(di->dev, "error reading flags\n");
 			return 0;
 		}
 		if (flags & BQ27000_FLAG_CHGS) {
 			dev_dbg(di->dev, "negative current!\n");
 			curr = -curr;
 		}
 	}

 	return curr * 1000;
 }

 /*
  * Return the battery Relative State-of-Charge
  * Or < 0 if something fails.
  */
 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
 {
 	int ret;
 	int rsoc = 0;

 	if (di->chip == BQ27500)
 		ret = bq27x00_read(BQ27500_REG_SOC, &rsoc, 0, di);
 	else
 		ret = bq27x00_read(BQ27000_REG_RSOC, &rsoc, 1, di);
 	if (ret) {
 		dev_err(di->dev, "error reading relative State-of-Charge\n");
 		return ret;
 	}

 	return rsoc;
 }

 static int bq27x00_battery_status(struct bq27x00_device_info *di,
 				  union power_supply_propval *val)
 {
 	int flags = 0;
 	int status;
 	int ret;

 	ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 	if (ret < 0) {
 		dev_err(di->dev, "error reading flags\n");
 		return ret;
 	}

 	if (di->chip == BQ27500) {
 		if (flags & BQ27500_FLAG_FC)
 			status = POWER_SUPPLY_STATUS_FULL;
 		else if (flags & BQ27500_FLAG_DSC)
 			status = POWER_SUPPLY_STATUS_DISCHARGING;
 		else
 			status = POWER_SUPPLY_STATUS_CHARGING;
 	} else {
 		if (flags & BQ27000_FLAG_CHGS)
 			status = POWER_SUPPLY_STATUS_CHARGING;
 		else
 			status = POWER_SUPPLY_STATUS_DISCHARGING;
 	}

 	val->intval = status;
 	return 0;
 }

 /*
  * Read a time register.
  * Return < 0 if something fails.
  */
 static int bq27x00_battery_time(struct bq27x00_device_info *di, int reg,
 				union power_supply_propval *val)
 {
 	int tval = 0;
 	int ret;

 	ret = bq27x00_read(reg, &tval, 0, di);
 	if (ret) {
 		dev_err(di->dev, "error reading register %02x\n", reg);
 		return ret;
 	}

 	if (tval == 65535)
 		return -ENODATA;

 	val->intval = tval * 60;
 	return 0;
 }

 #define to_bq27x00_device_info(x) container_of((x), \
 				struct bq27x00_device_info, bat);

 static int bq27x00_battery_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
 {
 	int ret = 0;
 	struct bq27x00_device_info *di = to_bq27x00_device_info(psy);

 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
 		ret = bq27x00_battery_status(di, val);
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 	case POWER_SUPPLY_PROP_PRESENT:
 		val->intval = bq27x00_battery_voltage(di);
 		if (psp == POWER_SUPPLY_PROP_PRESENT)
 			val->intval = val->intval <= 0 ? 0 : 1;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 		val->intval = bq27x00_battery_current(di);
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
 		val->intval = bq27x00_battery_rsoc(di);
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
 		val->intval = bq27x00_battery_temperature(di);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
 		ret = bq27x00_battery_time(di, BQ27x00_REG_TTE, val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 		ret = bq27x00_battery_time(di, BQ27x00_REG_TTECP, val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
 		ret = bq27x00_battery_time(di, BQ27x00_REG_TTF, val);
 		break;
 	default:
 		return -EINVAL;
 	}

 	return ret;
 }

 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
 {
 	di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 	di->bat.properties = bq27x00_battery_props;
 	di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 	di->bat.get_property = bq27x00_battery_get_property;
 	di->bat.external_power_changed = NULL;
 }

 /*
  * i2c specific code
  */

 static int bq27x00_read_i2c(u8 reg, int *rt_value, int b_single,
 			struct bq27x00_device_info *di)
 {
 	struct i2c_client *client = di->client;
 	struct i2c_msg msg[1];
 	unsigned char data[2];
 	int err;

 	if (!client->adapter)
 		return -ENODEV;

 	msg->addr = client->addr;
 	msg->flags = 0;
 	msg->len = 1;
 	msg->buf = data;

 	data[0] = reg;
 	err = i2c_transfer(client->adapter, msg, 1);

 	if (err >= 0) {
 		if (!b_single)
 			msg->len = 2;
 		else
 			msg->len = 1;

 		msg->flags = I2C_M_RD;
 		err = i2c_transfer(client->adapter, msg, 1);
 		if (err >= 0) {
 			if (!b_single)
 				*rt_value = get_unaligned_le16(data);
 			else
 				*rt_value = data[0];

 			return 0;
 		}
 	}
 	return err;
 }

 static int bq27x00_battery_probe(struct i2c_client *client,
 				 const struct i2c_device_id *id)
 {
 	char *name;
 	struct bq27x00_device_info *di;
 	struct bq27x00_access_methods *bus;
 	int num;
 	int retval = 0;

 	/* Get new ID for the new battery device */
 	retval = idr_pre_get(&battery_id, GFP_KERNEL);
 	if (retval == 0)
 		return -ENOMEM;
 	mutex_lock(&battery_mutex);
 	retval = idr_get_new(&battery_id, client, &num);
 	mutex_unlock(&battery_mutex);
 	if (retval < 0)
 		return retval;

 	name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
 	if (!name) {
 		dev_err(&client->dev, "failed to allocate device name\n");
 		retval = -ENOMEM;
 		goto batt_failed_1;
 	}

 	di = kzalloc(sizeof(*di), GFP_KERNEL);
 	if (!di) {
 		dev_err(&client->dev, "failed to allocate device info data\n");
 		retval = -ENOMEM;
 		goto batt_failed_2;
 	}
 	di->id = num;
 	di->chip = id->driver_data;

 	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
 	if (!bus) {
 		dev_err(&client->dev, "failed to allocate access method "
 					"data\n");
 		retval = -ENOMEM;
 		goto batt_failed_3;
 	}

 	i2c_set_clientdata(client, di);
 	di->dev = &client->dev;
 	di->bat.name = name;
 	bus->read = &bq27x00_read_i2c;
 	di->bus = bus;
 	di->client = client;

 	bq27x00_powersupply_init(di);

 	retval = power_supply_register(&client->dev, &di->bat);
 	if (retval) {
 		dev_err(&client->dev, "failed to register battery\n");
 		goto batt_failed_4;
 	}

 	dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);

 	return 0;

 batt_failed_4:
 	kfree(bus);
 batt_failed_3:
 	kfree(di);
 batt_failed_2:
 	kfree(name);
 batt_failed_1:
 	mutex_lock(&battery_mutex);
 	idr_remove(&battery_id, num);
 	mutex_unlock(&battery_mutex);

 	return retval;
 }

 static int bq27x00_battery_remove(struct i2c_client *client)
 {
 	struct bq27x00_device_info *di = i2c_get_clientdata(client);

 	power_supply_unregister(&di->bat);

 	kfree(di->bat.name);

 	mutex_lock(&battery_mutex);
 	idr_remove(&battery_id, di->id);
 	mutex_unlock(&battery_mutex);

 	kfree(di);

 	return 0;
 }

 /*
  * Module stuff
  */

 static const struct i2c_device_id bq27x00_id[] = {
 	{ "bq27200", BQ27000 },	/* bq27200 is same as bq27000, but with i2c */
 	{ "bq27500", BQ27500 },
 	{},
 };

 static struct i2c_driver bq27x00_battery_driver = {
 	.driver = {
 		.name = "bq27x00-battery",
 	},
 	.probe = bq27x00_battery_probe,
 	.remove = bq27x00_battery_remove,
 	.id_table = bq27x00_id,
 };

 static int __init bq27x00_battery_init(void)
 {
 	int ret;

 	ret = i2c_add_driver(&bq27x00_battery_driver);
 	if (ret)
 		printk(KERN_ERR "Unable to register BQ27x00 driver\n");

 	return ret;
 }
 module_init(bq27x00_battery_init);

 static void __exit bq27x00_battery_exit(void)
 {
 	i2c_del_driver(&bq27x00_battery_driver);
 }
 module_exit(bq27x00_battery_exit);

 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 MODULE_LICENSE("GPL");
	/*
	* BQ27x00 battery driver
	*
	* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
	* Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
	*
	* Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
	*
	* This package is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	*
	*/
	#include <linux/module.h>
	#include <linux/param.h>
	#include <linux/jiffies.h>
	#include <linux/workqueue.h>
	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/power_supply.h>
	#include <linux/idr.h>
	#include <linux/i2c.h>
	#include <asm/unaligned.h>

	#define DRIVER_VERSION "1.1.0"

	#define BQ27x00_REG_TEMP 0x06
	#define BQ27x00_REG_VOLT 0x08
	#define BQ27x00_REG_AI 0x14
	#define BQ27x00_REG_FLAGS 0x0A
	#define BQ27x00_REG_TTE 0x16
	#define BQ27x00_REG_TTF 0x18
	#define BQ27x00_REG_TTECP 0x26

	#define BQ27000_REG_RSOC 0x0B /* Relative State-of-Charge */
	#define BQ27000_FLAG_CHGS BIT(7)

	#define BQ27500_REG_SOC 0x2c
	#define BQ27500_FLAG_DSC BIT(0)
	#define BQ27500_FLAG_FC BIT(9)

	/* If the system has several batteries we need a different name for each
	* of them...
	*/
	static DEFINE_IDR(battery_id);
	static DEFINE_MUTEX(battery_mutex);

	struct bq27x00_device_info;
	struct bq27x00_access_methods {
	int (read)(u8 reg, int rt_value, int b_single,
	struct bq27x00_device_info *di);
	};

	enum bq27x00_chip { BQ27000, BQ27500 };

	struct bq27x00_device_info {
	struct device *dev;
	int id;
	struct bq27x00_access_methods *bus;
	struct power_supply bat;
	enum bq27x00_chip chip;

	struct i2c_client *client;
	};

	static enum power_supply_property bq27x00_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
	};

	/*
	* Common code for BQ27x00 devices
	*/

	static int bq27x00_read(u8 reg, int *rt_value, int b_single,
	struct bq27x00_device_info *di)
	{
	return di->bus->read(reg, rt_value, b_single, di);
	}

	/*
	* Return the battery temperature in tenths of degree Celsius
	* Or < 0 if something fails.
	*/
	static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
	{
	int ret;
	int temp = 0;

	ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
	if (ret) {
	dev_err(di->dev, "error reading temperature\n");
	return ret;
	}

	if (di->chip == BQ27500)
	return temp - 2731;
	else
	return ((temp >> 2) - 273) * 10;
	}

	/*
	* Return the battery Voltage in milivolts
	* Or < 0 if something fails.
	*/
	static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
	{
	int ret;
	int volt = 0;

	ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
	if (ret) {
	dev_err(di->dev, "error reading voltage\n");
	return ret;
	}

	return volt * 1000;
	}

	/*
	* Return the battery average current
	* Note that current can be negative signed as well
	* Or 0 if something fails.
	*/
	static int bq27x00_battery_current(struct bq27x00_device_info *di)
	{
	int ret;
	int curr = 0;
	int flags = 0;

	ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
	if (ret) {
	dev_err(di->dev, "error reading current\n");
	return 0;
	}

	if (di->chip == BQ27500) {
	/* bq27500 returns signed value */
	curr = (int)(s16)curr;
	} else {
	ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
	if (ret < 0) {
	dev_err(di->dev, "error reading flags\n");
	return 0;
	}
	if (flags & BQ27000_FLAG_CHGS) {
	dev_dbg(di->dev, "negative current!\n");
	curr = -curr;
	}
	}

	return curr * 1000;
	}

	/*
	* Return the battery Relative State-of-Charge
	* Or < 0 if something fails.
	*/
	static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
	{
	int ret;
	int rsoc = 0;

	if (di->chip == BQ27500)
	ret = bq27x00_read(BQ27500_REG_SOC, &rsoc, 0, di);
	else
	ret = bq27x00_read(BQ27000_REG_RSOC, &rsoc, 1, di);
	if (ret) {
	dev_err(di->dev, "error reading relative State-of-Charge\n");
	return ret;
	}

	return rsoc;
	}

	static int bq27x00_battery_status(struct bq27x00_device_info *di,
	union power_supply_propval *val)
	{
	int flags = 0;
	int status;
	int ret;

	ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
	if (ret < 0) {
	dev_err(di->dev, "error reading flags\n");
	return ret;
	}

	if (di->chip == BQ27500) {
	if (flags & BQ27500_FLAG_FC)
	status = POWER_SUPPLY_STATUS_FULL;
	else if (flags & BQ27500_FLAG_DSC)
	status = POWER_SUPPLY_STATUS_DISCHARGING;
	else
	status = POWER_SUPPLY_STATUS_CHARGING;
	} else {
	if (flags & BQ27000_FLAG_CHGS)
	status = POWER_SUPPLY_STATUS_CHARGING;
	else
	status = POWER_SUPPLY_STATUS_DISCHARGING;
	}

	val->intval = status;
	return 0;
	}

	/*
	* Read a time register.
	* Return < 0 if something fails.
	*/
	static int bq27x00_battery_time(struct bq27x00_device_info *di, int reg,
	union power_supply_propval *val)
	{
	int tval = 0;
	int ret;

	ret = bq27x00_read(reg, &tval, 0, di);
	if (ret) {
	dev_err(di->dev, "error reading register %02x\n", reg);
	return ret;
	}

	if (tval == 65535)
	return -ENODATA;

	val->intval = tval * 60;
	return 0;
	}

	#define to_bq27x00_device_info(x) container_of((x), \
	struct bq27x00_device_info, bat);

	static int bq27x00_battery_get_property(struct power_supply *psy,
	enum power_supply_property psp,
	union power_supply_propval *val)
	{
	int ret = 0;
	struct bq27x00_device_info *di = to_bq27x00_device_info(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
	ret = bq27x00_battery_status(di, val);
	break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	case POWER_SUPPLY_PROP_PRESENT:
	val->intval = bq27x00_battery_voltage(di);
	if (psp == POWER_SUPPLY_PROP_PRESENT)
	val->intval = val->intval <= 0 ? 0 : 1;
	break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	val->intval = bq27x00_battery_current(di);
	break;
	case POWER_SUPPLY_PROP_CAPACITY:
	val->intval = bq27x00_battery_rsoc(di);
	break;
	case POWER_SUPPLY_PROP_TEMP:
	val->intval = bq27x00_battery_temperature(di);
	break;
	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
	ret = bq27x00_battery_time(di, BQ27x00_REG_TTE, val);
	break;
	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
	ret = bq27x00_battery_time(di, BQ27x00_REG_TTECP, val);
	break;
	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
	ret = bq27x00_battery_time(di, BQ27x00_REG_TTF, val);
	break;
	default:
	return -EINVAL;
	}

	return ret;
	}

	static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
	{
	di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
	di->bat.properties = bq27x00_battery_props;
	di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
	di->bat.get_property = bq27x00_battery_get_property;
	di->bat.external_power_changed = NULL;
	}

	/*
	* i2c specific code
	*/

	static int bq27x00_read_i2c(u8 reg, int *rt_value, int b_single,
	struct bq27x00_device_info *di)
	{
	struct i2c_client *client = di->client;
	struct i2c_msg msg[1];
	unsigned char data[2];
	int err;

	if (!client->adapter)
	return -ENODEV;

	msg->addr = client->addr;
	msg->flags = 0;
	msg->len = 1;
	msg->buf = data;

	data[0] = reg;
	err = i2c_transfer(client->adapter, msg, 1);

	if (err >= 0) {
	if (!b_single)
	msg->len = 2;
	else
	msg->len = 1;

	msg->flags = I2C_M_RD;
	err = i2c_transfer(client->adapter, msg, 1);
	if (err >= 0) {
	if (!b_single)
	*rt_value = get_unaligned_le16(data);
	else
	*rt_value = data[0];

	return 0;
	}
	}
	return err;
	}

	static int bq27x00_battery_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	char *name;
	struct bq27x00_device_info *di;
	struct bq27x00_access_methods *bus;
	int num;
	int retval = 0;

	/* Get new ID for the new battery device */
	retval = idr_pre_get(&battery_id, GFP_KERNEL);
	if (retval == 0)
	return -ENOMEM;
	mutex_lock(&battery_mutex);
	retval = idr_get_new(&battery_id, client, &num);
	mutex_unlock(&battery_mutex);
	if (retval < 0)
	return retval;

	name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
	if (!name) {
	dev_err(&client->dev, "failed to allocate device name\n");
	retval = -ENOMEM;
	goto batt_failed_1;
	}

	di = kzalloc(sizeof(*di), GFP_KERNEL);
	if (!di) {
	dev_err(&client->dev, "failed to allocate device info data\n");
	retval = -ENOMEM;
	goto batt_failed_2;
	}
	di->id = num;
	di->chip = id->driver_data;

	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
	if (!bus) {
	dev_err(&client->dev, "failed to allocate access method "
	"data\n");
	retval = -ENOMEM;
	goto batt_failed_3;
	}

	i2c_set_clientdata(client, di);
	di->dev = &client->dev;
	di->bat.name = name;
	bus->read = &bq27x00_read_i2c;
	di->bus = bus;
	di->client = client;

	bq27x00_powersupply_init(di);

	retval = power_supply_register(&client->dev, &di->bat);
	if (retval) {
	dev_err(&client->dev, "failed to register battery\n");
	goto batt_failed_4;
	}

	dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);

	return 0;

	batt_failed_4:
	kfree(bus);
	batt_failed_3:
	kfree(di);
	batt_failed_2:
	kfree(name);
	batt_failed_1:
	mutex_lock(&battery_mutex);
	idr_remove(&battery_id, num);
	mutex_unlock(&battery_mutex);

	return retval;
	}

	static int bq27x00_battery_remove(struct i2c_client *client)
	{
	struct bq27x00_device_info *di = i2c_get_clientdata(client);

	power_supply_unregister(&di->bat);

	kfree(di->bat.name);

	mutex_lock(&battery_mutex);
	idr_remove(&battery_id, di->id);
	mutex_unlock(&battery_mutex);

	kfree(di);

	return 0;
	}

	/*
	* Module stuff
	*/

	static const struct i2c_device_id bq27x00_id[] = {
	{ "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
	{ "bq27500", BQ27500 },
	{},
	};

	static struct i2c_driver bq27x00_battery_driver = {
	.driver = {
	.name = "bq27x00-battery",
	},
	.probe = bq27x00_battery_probe,
	.remove = bq27x00_battery_remove,
	.id_table = bq27x00_id,
	};

	static int __init bq27x00_battery_init(void)
	{
	int ret;

	ret = i2c_add_driver(&bq27x00_battery_driver);
	if (ret)
	printk(KERN_ERR "Unable to register BQ27x00 driver\n");

	return ret;
	}
	module_init(bq27x00_battery_init);

	static void __exit bq27x00_battery_exit(void)
	{
	i2c_del_driver(&bq27x00_battery_driver);
	}
	module_exit(bq27x00_battery_exit);

	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
	MODULE_LICENSE("GPL");